The objectives of this grant are directed (1) to investigate pathologic changes in corneas caused by trauma, infection, dystrophies or degenerations. The studies are done by electron microscopy; (2) to study the causes of corneal graft failure in clinical and experimental situations; (3) to investigate from the morphological point of view the early cell alterations in graft reaction, the participation of T lymphocytes in this reaction and the phenomena of bacterial and fungal adherence to injured corneas; (4) we are also investigating the toxic effects of plastic or other synthetic materials corneal endothelium.